1. Field of the Invention
This invention relates in general to integral recording heads and suspensions, and more particularly, to a low mass magnetic head and suspension fabricated as one single structure using semiconductor processes and a method for making the same.
2. Description of Related Art
Moving magnetic storage devices, especially magnetic disk drives, are the memory device of choice. This is due to their expanded non-volatile memory storage capability together with a relatively low cost. Accurate retrieval of the stored information from these devices becomes critical, requiring the magnetic transducer to be positioned as close to the storage media as possible. Optimally, the transducer may actually contact the media.
Magnetic disk drives are information storage devices which utilize at least one rotatable magnetic media disk having concentric data tracks defined for storing data, a read/write transducer for reading data from and/or writing data to the various data tracks, a slider for supporting the transducer adjacent the data tracks typically in a flying mode above the storage media, a suspension assembly for resiliently supporting the slider and the transducer over the data tracks, and a positioning actuator coupled to the transducer/slider/suspension combination for moving the transducer across the media to the desired data track and maintaining the transducer over the data track center line during a read or a write operation. The transducer is attached to or is formed integrally with the slider which supports the transducer above the data surface of the storage disk by a cushion of air, referred to as an air bearing, generated by the rotating disk.
Alternatively, the transducer may operate in contact with the surface of the disk. Thus the suspension provides desired slider loading and dimensional stability between the slider and an actuator arm which couples the transducer/slider/suspension assembly to the actuator. The suspension is required to maintain the transducer and the slider adjacent the data surface of the disk with as low a loading force as possible. The actuator positions the transducer over the correct track according to the data desired on a read operation or to the correct track for placement of the data during a write operation. The actuator is controlled to position the transducer over the desired data track by shifting the combination assembly across the surface of the disk in a direction generally transverse to the data tracks.
The development of thin film magnetic head arrays has become the subject of increased interest, especially in the area of high speed, high density recording and retrieval of digital computer information on magnetic media.
Thin film magnetic heads are manufactured in a manner similar to a semiconductor integrated circuit elements, by film forming techniques such as vapor deposition, sputtering or the like or lithography such as photoengraving processes, etching, etc. These methods are advantageous in producing high-accuracy heads in large quantities.
There are two types of thin film magnetic heads hitherto known, i.e. a vertical head wherein a magnetic gap is formed in a direction perpendicular to a substrate surface (film thickness direction) and a horizontal head wherein a magnetic gap is formed along the substrate surface.
The vertical head is put to practical use because in the process of making vertical heads, it is easy to form a gap and vertical heads exhibit resistance against the sliding movement of a medium. On the other hand, the horizontal head makes it possible to complete whole processes, such as air bearing surface processing, in a substrate, since the surface of the head normally oriented to the medium is on the substrate side. Moreover, the depth of the magnetic gap is determined by the thickness of the film in the horizontal head, so that the depth of the gap is easily controlled during manufacture.
Horizontal thin film magnetic heads have become an object of attention owing to their advantages in dealing with narrow tracks with the recent progressive increase in magnetic recording density. Further, the performance of magnetic recording systems improves rapidly as the separation between the read/write head and the associated recording medium decreases. In rigid media systems, today, this separation is referred to as "flying height"--a reference relating to the fact that the conventional head, often referred to as a slider, is supported above the relatively moving medium surface by an air bearing.
Known methods for fabricating thin film magnetic head arrays typically consist of sequentially depositing thin film layers of magnetic, conductive, and insulative materials. The magnetic thin film layers (usually permalloy) form the magnetic yoke of the head structure and serve the function of concentrating magnetic flux according to desired geometries. The conductor thin film layer, typically gold or copper, forms the "turns" or windings around the magnetic yoke of the individual heads which induce a magnetic field when current is passed through them. The delineated layer of conductive thin films also provides electrical interconnection between the coil section of the heads and the power supply/addressing network which is used to activate the array. Finally, insulator thin film layers (polyimides, SiO.sub.2) are used to electrically isolate the various thin film conductor layers (especially in multi-turn head designs), as well as to provide precise gap spacing between upper and lower layers of the magnetic yoke.
The various thin film layers are typically deposited by a variety of techniques including vacuum deposition (sputtering, evaporation), electroplating, and spin-coating (e.g., for spin-on insulator materials). The resultant multi-layer thin film array structure is fabricated on a rigid substrate. For example, conventional magnetic heads are produced using ceramic wafers such as AlTiC and are suspended on stainless fixtures using physical or mechanical methods. The thin film layers are delineated into patterns (as required) using photolithographic masking and wet chemical or plasma etching techniques. The size and mass of the head are determined by the dimensions and composition of the wafer, respectively. The size is also limited by the physical and mechanical cutting methods used to cut the head from the wafer. More specifically, the length of the head is limited by the thickness of the wafer and the width and height of the head are limited by the physical cutting methods and tolerances.
Furthermore, conventional heads also require attachment to the suspensions and the wires for electrical contact must be bonded to the head assembly. These processes increase the size of the head/suspension assembly as well as contribute significantly to the cost.
It can be seen then that there is a need for a low mass magnetic head and suspension fabricated as one single structure using semiconductor processes.
It can also be seen that there is a need for an integral magnetic head and suspension with substantially reduced size and mass and a method for making the same.
It can also be seen that there is a need for a process for manufacturing an integral magnetic head and suspension that eliminates all head attach processes and alignment problems.